Minimally invasive surgical interventions are rapidly increasing in popularity. This is due to the development of new interventional techniques and the desire on the part of both clinicians and patients to decrease procedure-related morbidity and trauma. Minimally invasive interventions are done using catheters, needles, or other instruments that are introduced, targeted, and manipulated without the benefit of the direct instrument visualization afforded by the usual surgical exposure. Using such procedures minimizes trauma to the patient, but severely restricts the physician's view of the underlying anatomy. In contrast, image-guided surgery uses preoperative magnetic resonance imaging (MRI) or computed tomography (CT) scans to guide invasive surgical procedures, providing the physician with some guidance.
Typical image guided surgery systems are based on bony landmarks, especially with regard to applications in the brain and spine. One example of a device used for guiding invasive surgical procedures is seen in U.S. Pat. No. 5,558,091. The system described therein includes a magnetic positioning system that utilizes a reference probe, an instrument probe, and a magnetic field to magnetically track the instrument probe in the area of interest.
Other systems and methods that provide for efficient access of internal structures of the body are needed.